Protein conformations have been investigated by calculations which include either short and medium range or long range interactions. These include 1) predictions of regular secondary regions, with a method which is not dependent on X-ray crystals, and 2) investigations of folding pathways of proteins with a simple model in which the native conformation is favored. Conformational invariance in spite of larger sequence variations has been investigated for several families of proteins. Conformational agreement for pairs of residues was observed to be greater than sequence agreement by 20 to 50%. From the second calculations which include long range interactions, definite folding pathways are obtained for pancreatic trypsin inhibitor, myoglobin, ribonuclease, concanavalin A, and lysozyme. The activated state for the folding-unfolding process is found to correspond to the appearance of long range interactions. In all cases only one or two regions of growing nuclei are observed. More detailed models of the specific nature of tertiary interactions are being developed.